. A manual for the study of insects. Insects. INSECTS AND THEIR NEAR RELATIVES. 13. Fig, 6.—Lower side of cephalothorax of a spider: tnd, man- dible ; mx^ maxilla ; /, palpus ; /, lower lip; J, sternum. appendages—two pairs of jaws, and four pairs of legs. The first pair of jaws are the mandibles (manMi-bles), the second, the maxillce (max-iriae). The mandibles (Fig. 6, md) He in front of and above the mouth, and consist each of two or three segments. They serve for seizing prey, and often also for kiUing it. In many books they are termed the chelicerce (che-lic'e-rse). The 7naxillce (Fig. 6,
. A manual for the study of insects. Insects. INSECTS AND THEIR NEAR RELATIVES. 13. Fig, 6.—Lower side of cephalothorax of a spider: tnd, man- dible ; mx^ maxilla ; /, palpus ; /, lower lip; J, sternum. appendages—two pairs of jaws, and four pairs of legs. The first pair of jaws are the mandibles (manMi-bles), the second, the maxillce (max-iriae). The mandibles (Fig. 6, md) He in front of and above the mouth, and consist each of two or three segments. They serve for seizing prey, and often also for kiUing it. In many books they are termed the chelicerce (che-lic'e-rse). The 7naxillce (Fig. 6, mx) lie just behind the mandibles, one on each side of the mouth. Each maxilla bears a large feeler or palpus (Fig. 6,/). These palpi vary greatly in form ; frequently they resemble legs; hence many Arachnida appear to have five pairs of legs. The palpi are often so largely developed that each maxilla ap- pears to be merely the first segment of its leg-like palpus. These appendages are often called the pedipalpi (ped-i-paFpi). But as the name Pedipalpi is applied to one of the or- ders of the Arachnida, we will call these ap- pendages the palpi. The legs of Arachnida consist typically of seven parts (Fig. 7), which are named, begin- ning with the one next to the body, as fol- lows : I, coxa (cox'a); 2, trochanter (tro-chan'- ter); ^nur (fe'mur); ^.patella (pa-teFla); 5, tibia (tib'i-a); 6, metatarsus (met-a-tar'sus) ; and 7, tarsus (tar'sus). The tarsus may be composed of several segments, and is usually furnished with claws. Two forms of breathing organs are found in this class : one, tracheae, resembling the tracheae of insects, described in the chapter on the anatomy of insects ; and the other, tracheal lungs or lung sacs, which consist of many leaf-like plates enclosed in a sac. Both forms open by paired spira- cles, which are usually situated on the lower side of some of the abdominal Please note that these images are extracted from scanned page images t
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectinsects, bookyear1895
